1. Field of the Invention
The invention generally relates to optical systems for coupling light into a single optic fiber or fiber bundle.
2. Description of Related Art
A variety of optical coupling systems have been developed for coupling light from a high intensity light source such as an arc lamp into an optical fiber bundle or a single optic fiber. The light coupled into the bundle or single fiber may be used, for example, for medical illumination purposes such as for use with a surgical luminaire, head lamp, endoscope or borescope. For medical applications, in particular, it is necessary to couple as much light into the bundle or single fiber as possible to provide for adequate illumination of a surgical field when using a surgical luminaire, head lamp, etc. Accordingly, precise alignment of the light source with optical components of the coupler is required to ensure that a sufficient amount of light is coupled into the fiber or bundle. Such is particularly critical for coupling light into a single optic fiber which has a much smaller overall entry aperture than a fiber bundle. To ensure precise alignment, the optical source is typically rigidly mounted to an integrated assembly which also includes all or most of the internal optical components of the coupling system. For example, the source may be mounted to an integrated assembly which also includes one or more primary and secondary mirrors aligned for reflecting light from the source into the single fiber or fiber bundle. An integrated assembly is employed to prevent any displacement between the source and the optical components which may prevent an adequate amount of light to be coupled into the single fiber or fiber bundle. Such displacements may occur as a result of the optical coupler being bumped or jarred, perhaps by medical personnel, or may result from uneven heating of separate mounting components holding the source and optical components.
Although the use of an integrated assembly helps ensure adequate alignment of the source and optical components, the source itself cannot be easily and inexpensively replaced. Replacement is required if the source fails entirely. Replacement is also typically performed after the source has been operated for a predetermined number of hours. If integrated, the source and optical components must both be replaced. This is typically achieved by the user removing the integrated assembly and shipping the assembly back to the vendor who installs and aligns a new source. The light source itself cannot simply be replaced by the user because precise alignment of the source would not be ensured. Failure to properly align the source may result in physical damage to the interior of the optical coupler, particularly if light is focused to a position slightly offset from the entrance aperture of the single fiber or fiber bundle thereby resulting in overheating. Such overheating may ruin the fiber and perhaps the entire optical coupling system as well.
Costs associated with replacing the entire integrated assembly can be significant. Moreover, in circumstances where the source burns out, the user may be unable to use the optical system for a day or two before a replacement assembly can be provided.
Accordingly, it would be desirable to provide an improved optical coupler system which allows the optical source to be replaced without also requiring replacement of the optical components yet still ensuring precise alignment of the source with the optical components. It is to these ends that the present invention is drawn.